Maharashtra Board Class 7 Chapter 5 Set 25 Operations on Rational Numbers Solutions

Question 1. Simplify the following expressions.
(i) 50 x 5 ÷ 2 + 24
(ii) (13 x 4) ÷ 2 - 26
(iii) 140 ÷ [(-11) x (-3) - (-42) ÷ 14 - 1)]
(iv) {(220 - 140) + [10 x 9 + (-2 x 5) ]} - 100
(v) \( \frac{3}{5} + \frac{3}{8} \div \frac{6}{4} \)
Answer:
(i) \( 50 \times 5 \div 2 + 24 = 250 \div 2 + 24 \)
\( = 125 + 24 \)
\( = 149 \)
(ii) \( (13 \times 4) \div 2 - 26 \)
\( = 52 \div 2 - 26 \)
\( = 26 - 26 \)
\( = 0 \)
(iii) \( 140 \div [(-11) \times (-3) - (-42) \div 14 - 1)] \)
\( = 140 \div [33 + 42 \div 14 - 1] \)
\( = 140 \div [33 + 3 - 1] \)
\( = 140 \div 35 \)
\( = 4 \)
(iv) \( \{(220 - 140) + [10 \times 9 + (-2 \times 5) ]\} - 100 \)
\( = \{80 + [90 - 10]\} - 100 \)
\( = \{80 + 80\} - 100 \)
\( = 160 - 100 \)
\( = 60 \)
(v) \( \frac{3}{5} + \frac{3}{8} \div \frac{6}{4} \)
\( = \frac{3}{5} + \frac{3}{8} \times \frac{4}{6} \)
\( = \frac{3}{5} + \frac{1}{4} \)
\( = \frac{12}{20} + \frac{5}{20} \)
\( = \frac{12+5}{20} \)
\( = \frac{17}{20} \)
In simple words: These problems require applying the order of operations (BODMAS/PEMDAS) correctly, performing multiplication, division, addition, and subtraction in the specified sequence to simplify each expression. For fractions, division becomes multiplication by the reciprocal.

🎯 Exam Tip: Always remember the BODMAS/PEMDAS rule. Misapplying the order of operations is a common mistake that leads to incorrect answers. Pay close attention to negative signs and fraction arithmetic.

Maharashtra Board Class 7 Maths Chapter 5 Operations On Rational Numbers Practice Set 25 Intext Questions And Activities

Question 1. Use the signs and numbers in the boxes and form an expression such that its value will be 112. (Textbook pg. no. 42)
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
[+ x ÷ -]
Answer: \( \{3 + (6 \times 7) + (9 \div 3)\} + \{- 8 + 8 \times 9\} \)
In simple words: The goal is to combine the given numbers and arithmetic operators to construct an expression that evaluates to 112. This involves trial and error or strategic placement of operations and numbers.

🎯 Exam Tip: For such creative problem-solving questions, show your complete expression clearly. While multiple solutions may exist, a correct expression demonstrating understanding of operations and achieving the target value will fetch full marks.

Note: The above problem has many solutions. Students may write solution other than the one given.